Incineration of hospital refuse

ABSTRACT

An incinerator for hospital refuse in which an auxiliary chamber and a waste heat boiler are provided with a mechanical grate for separating slag and solid combustion residue. The waste heat boiler is connected to the auxiliary chamber by the outlet draught of the auxiliary chamber.

'United States Patent Stloukal et al.

[451 Dec. 16, 1975 INCINERATION OF HOSPITAL REFUSE Inventors: Mojmir Stloukal; Zdenek Syrovatka;

Milan Dolezel; Karel Stripek, all of Brno, Czechoslovakia Prvni Brnenska strojirna, Brno, Czechoslovakia Filed: Aug. 20, 1974 Appl. No.: 499,087

Assignee:

US. Cl 110/10; 110/38 Int. Cl. F23G 5/00; F228 1/22 Field of Search 110/8 R, 10, 38

[56] References Cited UNITED STATES PATENTS 2,015,842 10/1935 Christensen v.110/10 3,016,849 1/1962 Markle, Jr. et a1. 110/38 X 3,208,411 9/1965 Urban et al 110/10 3,212,465 10/1965 Cates, Jr. et a1 110/38 3,393,652 7/1968 Connell 110/10 3,651,770 3/1972 HOtti a. 110/38 Primary Examiner-l enneth W. Sprague Attorney, Agent, or Firm-Burgess, Ryan and Wayne [5 7 1 ABSTRACT An incinerator for hospital refuse in which an auxiliary chamber and a waste heat boiler are provided with a mechanical grate for separating slag and solid combustion residue. The waste heat boiler is connected to the auxiliary chamber by the outlet draught of the auxiliary chamber.

3 Claims, 2 Drawing Figures US. Patent Dec. 16,1975

INCINERATION OF HOSPITAL REFUSE.

This invention relates to an incinerator used for the incineration of refuse and in particular to the incineration of hospital refuse.

The liquidation of refuse produced by modern society is a world-wide problem, the solution of which is more and more difficult with the growing quantity of the deposited refuse and the diminishing surfaces suitable for its disposition. These problems were even more acute with 1105! ital refuse which was often deposited in a landfill or dump area. The removal of hospital refuse to areas of this type is totally inadmissible for hygienic and sanitary reasons. I

Nowadays, hospital refuse is generally incinerated in single-purpose sanitary furnaces with small incinerating capacity. From the point of view of modern combustion techniques, the design of such a furnace is simple. Its operation, however, is accompanied by unfavorable phenomena which is characteristic of combustion on-a manually operated stationary grate.

When adding fresh refuse-fuel, the temperature in the furance is lowered. Owing to the increase in the resistance of the fuel layer generating by the addition of fresh refuse, it is impossible to supply through the grate the necessary quantity of combustion air needed for perfect combustion of the distillation gases and vapors developed during furnace operation. After degasification of the fuel, which takes a short time, a rarefied gas layer remains in the furnace which causes only a slight resistance. For this reason, the shortage of air prevailing in the distillation phase is diminished little by little and, after the total degasification, changes gradually into an excess of air. During one phase of the combustion process, i.e., between two additions of fuel, soot and a dense, bad smelling smoke develops in the furnace.

The above problem is aggravated by the use of a battery of furances. The extra furnaces, althoughyielding greater incinerating capacity, worsen the conditions of work for the operators, who are in direct contact with the hospital refuse and'the dust from the solid combustion residue. Additionally, the hygienic conditions and the cleanliness of the area of the whole hospital and its surroundings are influenced by gas and solid exhalations from the incinerator.

The present invention seeks to provide an-efficient, economic and hygienic incinerator used particularly for hospital refuse.

According to the invention, there is providedan incinerator comprising an auxiliary chamber with a mechanical grate separated from the proper waste-heat boiler. The waste heat boiler is equipped with independent firing capability. The auxiliary chamber is interconnected by an outlet draught from the auxiliary chamber to the combustion chamber of the waste-heat boiler or above or below the burners of the independent firing means.

The incinerator according to the invention is particularly intended for incinerating hospital refuse such as reconstituted packing material, paper, plaster dressing, packing, surgery refuse, dead animals, glass, tinsand cans, etc. r a

According to the invention, there is further provided a mechanical grate comprising at least three terraced platforms. The first grate platform is movable horizontally and is also used as the movable bottom of the hopper. The second grate platform and the third grate platform consist of fixed bars and movable bars arranged in a checkerboard layout. Both are provided with adjustable travel and velocity, and the movable bars of the second platform and the third platform are constructed to move in the opposing directions.

Because the auxiliary chamber is separate from the main incinerator or boiler, it can be put into operation at any time. The boiler, having its own firing capability, remains in continuous operation for the continuous production of steam. All the combustion gases are led through the auxiliary chamber and the boiler so that no bacteria from the refuse can escape into the atmosphere which renders the combustion gases innocuous and reduces smell to a tolerable or nonexistent level. By adjusting the length of travel and the velocity of the movable bars of the second and third grate surfaces, an acceleration or slow-down in the combustion of refuse, the supply of the refuse to the grate, and the relative reciprocal movement of the refuse particles both in the cross and longitudinal directions is obtained. Further still, the caking or agglomeration of refuse into big pieces is prevented. The caking of the refuse into big pieces is prevented by the mechanical grate. This enhances the access of the radiant heat into the refuse layer and the aerodynamic conditions of the combustion air in the refuse layer are ameliorated. The grate is covered uniformly by the refuse layer and the combustion is distributed over a big grate surface. According to the refuse characteristics, it is possible during operation either to slow down or to speed up the degree and speed of refuse advance on the grate whereby the time the refuse stays on the grate is lengthened or shortened as necessary.

The incinerator according to the invention and the mechanization of the boiler-house eliminate totally the need for manual operation, especially manual operation of the grate firing and slag removal from the grate. As a result, the best hygienic conditions are obtained as the operators do not come into contact either with the refuse or the dusty solid combustion residue and are thus protected agains infectious illnesses. The incinerator serves not only for the efficient liquidation of refuse by incineration, but it also produces technological steam necessary for the operation of the hospital.

By incinerating all combustible substances, the volume of the refuse is essentially reduced. The formed slag is sterile and does not contain putrefactive organic substances. In the case of incinerating refuse which is noxious, the perfect incineration of such refuse and the conduction of all the combustion gases through the combustion chamber prevent bacteria from escaping to the atmosphere. The combustion gases are innocuous from a hygienic point of view and do not smell badly. In order not to pollute the surroundings by exhalation from the incinerator, natural gas or other fuel may be used for stabilizing the combustion of the refuse.

The incinerator according to the invention makes it possible to achieve good pre-drying, pre-heating, a timely inflammation and a good bum-up of the refuse which has a highly caloric value. The caloric value of the refuse varies to a considerable degree. The quantitative part of the main components contain either ash or water but few flammable substances. Considering the low caloric contents and thus the small caloric value, such refuse is not capable of burning alone and must be stabilized by a valuable energetic fuel.

A specific embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic representation of the total incinerator;

FIG. 2 is a detail view of the mechanical grate in accordance with the invention.

The refuse hopper 1 is provided with an adjustable layer baffie plate 3 for regulating the height of the refuse layer and for closing the hopper against the grate combustion chamber. The bottom of the refuse hopper 1 comprises the first grate platform 2 behind whichare located the second grate platform 4 and the third grate platform 7 which are terraced downwardly from the first grate platform.

The first grate platform 2 has all the bars 6 along the width of the grate movable so that they form the discharging device for the refuse from the hopper. The second grate platform 4 is made alternatively of fixed bars 5 and movable bars 6 along the width of the grate. In an analogous way is made the third grate platform 7. Each fixed bar 5 of the grate platform 4 is linked to the movable bar 6 of the grate platform 7. The arrangement of fixed bars 5 and movable bars 6 of the second grate platform 4 and the third grate platform 7is made in an alternative way as a checkerboard outlay. The movement of the movable bars 6 of the second grate platform 4 and those of the third grate platform 7 are counter to each other, as these are moved by a system of two-armed levers and a drive conversion unit (not shown).

The grate is longitudinally divided at least into three air tight zones 8. The quantity of the hot combustion air may be regulated by flap valves 9 in the last two air zones.

In the grate combustion chamber are located gas or oil burners 1 1 for igniting and stabilizing the combustion of refuse. Secondary air 12 is blown into the grate combustion chamber in order to mix the combustion gases and to provide the air necessary for the combustion of the combustible gases. The solid combustion residue, i.e., the substances which fall through the grates, and the slag, are transported out of the incinerator by the slag removal device 15.

The brick wall of the auxiliary chamber 16 in which the mechanical grate is located is made of a combination of heavy brickwork and vaulted roofs of fireproof and insulating material, respectively, in combination with tube walls and a suspended light brickwork. The auxiliary chamber 16 is made as an independent unit which can be placed between the incinerator and any type of boiler 17. The chamber of the grate combustion chamber continues past the outlet after burner draught 18, which leads into the proper boiler 17 above the burners 20, as shown, or under the same if such is desired.

The refuse is charged in doses into the refuse hopper l, the bottom of which is provided by the first grate platform 2. By the horizontal alternative movement of the first grate platform 2 both backward and forward, the clogging of the refuse hopper 1 is prevented as the refuse is pushed out continuously through its bottom. The height of the refuse layer is adjusted by the layer baffle plate 3. The layer baffle plate 3 and the first grate platform 2 regulate the quantity of refuse supplied to the grate, ensure the uniform dispensing of the refuse along the width of the grate, and improve the aerodynamic conditions in the refuse layer on the grate.

When moving the movable bars 6 of the grate platforms 4, 7 the refuse falls from one grate platform to the successive one. The bars 5, 6 arranged in a checkerboard layout make it possible to achieve not only the supply of refuse from the refuse hopper 1 to the end of the grate but also both the longitudinal and cross reciprocal relative movement of the refuse particles in the layer.

The preparation of the refuse for incineration is further intensified by the fact that the hot combustion gases are forced to flow owing to the configuration of the grate combustion chamber in the direction of the arrow 10, which flows against the direction in which the refuse supplied to the grate. It is possible to regulate the quantity of the hot combustion air by means of the flap valves 9 in the last two air zones 9.

Cold secondary air 12 is blown into the grate combustion chamber in order to mix the combustion gases and to compensate for the possible lack of air necessary for the combustion of combustible gases.

Burners 11 for burning either liquid or gaseous energetic fuel are located above the grate for igniting and stabilizing the combustion of refuse considering the caloric variability of its composition. The position of burners 11 are chosen so as to achieve the best combustion of the refuse on the grate.

The solid combustion residue, i.e., the substances which have fallen through the grate in the direction of the arrow 13, and the slag which has fallen through in the direction of the arrowv 14, fall into the slag removal device 15. The solid residue is removed from the slag removal device 15 in a wet and dustless state and its further transport may be carried out in any convenient way.

The auxiliary chamber 16 is made as an independent unit which may be located before any type of boiler 17. The combustion gases coming out of the auxiliary chamber 16 by the outlet draught 18 are led in the direction of the arrow 19. into the proper boiler 17 in the space above thebumers 20.

By properly selecting the shape of the outlet draught a change in the velocity of combustion gases may be obtained. The sorting out and the combustion of fine particles in suspension respectively are obtained in this manner. This circumstance diminishes the percentage of flying ash from the auxiliary chamber 16 into the proper boiler 17.

The described incinerator serves not only for an efficient and innocuous liguidation of hospital refuse by incineration, but simultaneously aids the production of technological steam which is necessary for the opera tion of a hospital. The incinerator according to the invention is a complex, hygienic and economic solution of the problems connected with the liquidation of hospital refuse by incineration and contributes to the elimination of the pollution of the environment and surroundings of a town.

Although the incinerator according to the invention is especially suitable for incinerating refuse, it can be used with advantage for combustion of all fuels of inferior quality with a very low caloric value.

Modifications in and to the above described embodiment will occur to those skilled in the art. It is intended to cover all such modifications which fall within the spirit and scope of the invention as defined in the claims appended hereto.

What is claimed is:

1. An incinerator for the incineration of refuse, comprising an auxiliary chamber having at least three serially arranged mechanical grate platforms, a hopper for the discharge of the refuse above the first of the grate platforms, each of the platforms comprising a plurality of spaced bars, means for reciprocating the bars of the first platform, means for reciprocally moving alternate bars of a second of the three platforms, the bars between the alternate bars of the second platform being fixed in position, a portion of the bars of the second platform being in vertical alignment with the bars of a third of the platforms, means for moving the bars of the third platform in phase opposition with the bars of the second platform, the bars of the third platform comprising a plurality of fixed bars and a plurality of movable bars, the fixed bars of the second platform being in partial vertical alignment with the movable bars of the third platform and the movable bars of the second platform being in partial vertical alignment with the fixed bars of the third platform, the incinerator further comprising a waste heat boiler, said grate platforms being separated from the waste heat boiler, said waste heat boiler being equipped with an independent ignition means, said auxiliary chamber being interconnected by an outlet draught to a combustion chamber of the waste heat boiler. 1

2. An incinerator, as recited in claim 1, further comprising a separate air supply zone beneath each of the grates.

3. An incinerator, as recited in claim 2, further comprising a regulating valve in at least one of the air supply zones. 

1. An incinerator for the incineration of refuse, comprising an auxiliary chamber having at least three serially arranged mechanical grate platforms, a hopper for the discharge of the refuse above the first of the grate platforms, each of the platforms comprising a plurality of spaced bars, means for reciprocating the bars of the first platform, means for reciprocally moving alternate bars of a second of the three platforms, the bars between the alternate bars of the second platform being fixed in position, a portion of the bars of the second platform being in vertical alignment with the bars of a third of the platforms, means for moving the bars of the third platform in phase opposition with the bars of the second platform, the bars of the third platform comprising a plurality of fixed bars and a plurality of movable bars, the fixed bars of the second platform being in partial vertical alignment with the movable bars of the third platform and the movable bars of the second platform being in partial vertical alignment with the fixed bars of the third platform, the incinerator further comprising a waste heat boiler, said grate platforms being separated from the waste heat boiler, said waste heat boiler being equipped with an independent ignition means, said auxiliary chamber being interconnected by an outlet draught to a combustioN chamber of the waste heat boiler.
 2. An incinerator, as recited in claim 1, further comprising a separate air supply zone beneath each of the grates.
 3. An incinerator, as recited in claim 2, further comprising a regulating valve in at least one of the air supply zones. 